Aim: To study the rate of blastocyst formation in 4-cell mouse embryos after laser destruction of one blastomere, with or without microsurgical removal of the destroyed blastomere.
Methods: Mouse embryos were randomly allocated to two control and two experimented groups. Control embryos were either non-manipulated (117 embryos) or underwent laser ablation of zona only (114 embryos). Experimented embryos had laser destruction of zona and the adjacent blastomeres. Destroyed blastomeres were either left in situ (115 embryos) or were microsurgically removed (107 embryos). They were cultured in sequential media for 72 h and were assessed for cleavage/morula arrest and blastocyst formation rates.
Results: Embryos arrested at cleavage/morula stages were higher when destroyed blastomeres remained in situ (30.4%) than when they were immediately removed (15.0%, P < 0.05). Blastocysts in the group with immediate removal of the destroyed blastomeres (85%) were significantly higher than when destroyed blastomeres were left in situ (69.6%, P < 0.05). Blastocyst formation in the repaired embryos was significantly lower than the non-manipulated (91.5%) and the manipulated controls (94.8%, P < 0.05). Hatching blastocysts were highest in control embryos with zonal ablation (72.8%). Proportions of hatching/hatched blastocysts in embryos, with or without removal of destroyed blastomeres, were not significantly different (39.3% and 33.9%, respectively). The percentage of embryonic loss during an attempt at microsurgical repair was 6.1%.
Conclusion: Microsurgical removal of destroyed blastomere was effective in restoring blastocyst development. It could reduce the rate of cleavage/morula arrest.
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http://dx.doi.org/10.1111/j.1447-0756.2006.00371.x | DOI Listing |
Bioessays
January 2024
Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
Fertilization triggers cytoplasmic movements in the frog egg that lead in mysterious ways to the stabilization of β-catenin on the dorsal side of the embryo. The novel Huluwa (Hwa) transmembrane protein, identified in China, is translated specifically in the dorsal side, acting as an egg cytoplasmic determinant essential for β-catenin stabilization. The Wnt signaling pathway requires macropinocytosis and the sequestration inside multivesicular bodies (MVBs, the precursors of endolysosomes) of Axin1 and Glycogen Synthase Kinase 3 (GSK3) that normally destroy β-catenin.
View Article and Find Full Text PDFJBRA Assist Reprod
September 2023
Division of Reproductive Medicine, Department of Obstetrics and Gynecology, Chiang Mai University, Chiang Mai, Thailand.
Objective: We evaluated the effects of crocin supplementation during culture of intact and half-destroyed four-cell mouse embryos. Outcomes measured included rate of cleavage arrest, blastocyst formation, and blastocyst cell number.
Methods: We used laser to create two zonal holes without blastomere destruction in Groups 1 (n=100) and 2 (n=100), and to destroy two of the four blastomeres in Groups 3 (n=150) and 4 (n=150).
Curr Biol
September 2023
Laboratory of Biology and Modeling of the Cell, Ecole Normale Superieure de Lyon, CNRS UMR5239, Inserm U1293, University Claude Bernard Lyon 1, Lyon, France. Electronic address:
Some species undergo programmed DNA elimination (PDE), whereby portions of the genome are systematically destroyed in somatic cells. PDE has emerged independently in several phyla, but its function is unknown. Although the mechanisms are partially solved in ciliates, PDE remains mysterious in metazoans because the study species were not yet amenable to functional approaches.
View Article and Find Full Text PDFThe complexity of predicting embryo development potential at the cleavage stages and the emergence of epigenetic risks during prolonged in vitro culture of pre-implantation embryos made it more advantageous to transfer embryos at the morula stage to the uterine cavity. The criteria for estimating embryos at this stage that allow prediction of cryopreservation outcomes have been poorly described. All day 4 embryos (n = 224) were graded 1, 2, 3, 4 or 5 according to blastomere compaction degree (BCD = 100, 75, 50, 25 or 0%, respectively) and the survival and blastocyst formation rate of these morulae were studied after cryopreservation.
View Article and Find Full Text PDFHum Reprod
August 2014
Department of Stem Cells and Developmental Biology at the Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, PO Box 19395-4644, Tehran, Iran Department of Developmental Biology, University of Science and Culture, ACECR, Tehran, Iran
Study Question: Can transforming growth factor β (TGFβ) inhibition promote ground state pluripotency of embryonic stem cells (ESCs) from single blastomeres (SBs) of cleavage embryos in different mouse stains?
Summary Answer: Small molecule suppression of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and TGFβ signaling (designated as R2i) can enhance the generation of mouse ESCs from SBs of different cleavage stage embryos compared with the dual suppression of ERK1/2 and glycogen synthase kinase 3 (GSK3), designated as 2i, regardless of the strain of mouce.
What Is Known Already: It is known that chemical inhibition of TGFβ promotes ground state pluripotency in the generation and sustenance of naïve ES cells from mouse blastocysts compared with the well-known 2i condition. However, the positive effect of this inhibition on mouse ESCs from early embryonic SBs remains obscure.
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